linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>,
	Hannes Reinecke <hare@suse.de>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Christoph Hellwig <hch@lst.de>,
	axboe@kernel.dk, mpe@ellerman.id.au, keith.busch@intel.com,
	peterz@infradead.org, LKML <linux-kernel@vger.kernel.org>,
	linux-scsi@vger.kernel.org,
	Sumit Saxena <sumit.saxena@broadcom.com>,
	Shivasharan Srikanteshwara 
	<shivasharan.srikanteshwara@broadcom.com>
Subject: Re: system hung up when offlining CPUs
Date: Mon, 2 Oct 2017 12:36:52 -0400	[thread overview]
Message-ID: <78ce7246-c567-3f5f-b168-9bcfc659d4bd@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1709161630580.2105@nanos>



On 09/16/2017 11:02 AM, Thomas Gleixner wrote:
> On Sat, 16 Sep 2017, Thomas Gleixner wrote:
>> On Thu, 14 Sep 2017, YASUAKI ISHIMATSU wrote:
>>> Here are one irq's info of megasas:
>>>
>>> - Before offline CPU
>>> /proc/irq/70/smp_affinity_list
>>> 24-29
>>>
>>> /proc/irq/70/effective_affinity
>>> 00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,3f000000
>>>
>>> /sys/kernel/debug/irq/irqs/70
>>> handler:  handle_edge_irq
>>> status:   0x00004000
>>> istate:   0x00000000
>>> ddepth:   0
>>> wdepth:   0
>>> dstate:   0x00609200
>>>             IRQD_ACTIVATED
>>>             IRQD_IRQ_STARTED
>>>             IRQD_MOVE_PCNTXT
>>>             IRQD_AFFINITY_SET
>>>             IRQD_AFFINITY_MANAGED
>>
>> So this uses managed affinity, which means that once the last CPU in the
>> affinity mask goes offline, the interrupt is shut down by the irq core
>> code, which is the case:
>>
>>> dstate:   0x00a39000
>>>             IRQD_IRQ_DISABLED
>>>             IRQD_IRQ_MASKED
>>>             IRQD_MOVE_PCNTXT
>>>             IRQD_AFFINITY_SET
>>>             IRQD_AFFINITY_MANAGED
>>>             IRQD_MANAGED_SHUTDOWN  <---------------
>>
>> So the irq core code works as expected, but something in the
>> driver/scsi/block stack seems to fiddle with that shut down queue.
>>
>> I only can tell about the inner workings of the irq code, but I have no
>> clue about the rest.
> 
> Though there is something wrong here:
> 
>> affinity: 24-29
>> effectiv: 24-29
> 
> and after offlining:
> 
>> affinity: 29
>> effectiv: 29
> 
> But that should be:
> 
> affinity: 24-29
> effectiv: 29
> 
> because the irq core code preserves 'affinity'. It merily updates
> 'effective', which is where your interrupts are routed to.
> 
> Is the driver issuing any set_affinity() calls? If so, that's wrong.
> 
> Which driver are we talking about?

We are talking about megasas driver.
So I added linux-scsi and maintainers of megasas into the thread.

Thanks,
Yasuaki Ishimatsu

> 
> Thanks,
> 
> 	tglx
> 

  reply	other threads:[~2017-10-02 16:36 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-08 19:25 system hung up when offlining CPUs YASUAKI ISHIMATSU
2017-08-09 11:42 ` Marc Zyngier
2017-08-09 19:09   ` YASUAKI ISHIMATSU
2017-08-10 11:54     ` Marc Zyngier
2017-08-21 12:07       ` Christoph Hellwig
2017-08-21 13:18       ` Christoph Hellwig
2017-08-21 13:37         ` Marc Zyngier
2017-09-07 20:23           ` YASUAKI ISHIMATSU
2017-09-12 18:15             ` YASUAKI ISHIMATSU
2017-09-13 11:13               ` Hannes Reinecke
2017-09-13 11:35                 ` Kashyap Desai
2017-09-13 13:33                   ` Thomas Gleixner
2017-09-14 16:28                     ` YASUAKI ISHIMATSU
2017-09-16 10:15                       ` Thomas Gleixner
2017-09-16 15:02                         ` Thomas Gleixner
2017-10-02 16:36                           ` YASUAKI ISHIMATSU [this message]
2017-10-03 21:44                             ` Thomas Gleixner
2017-10-04 21:04                               ` Thomas Gleixner
2017-10-09 11:35                                 ` [tip:irq/urgent] genirq/cpuhotplug: Add sanity check for effective affinity mask tip-bot for Thomas Gleixner
2017-10-09 11:35                                 ` [tip:irq/urgent] genirq/cpuhotplug: Enforce affinity setting on startup of managed irqs tip-bot for Thomas Gleixner
2017-10-10 16:30                                 ` system hung up when offlining CPUs YASUAKI ISHIMATSU
2017-10-16 18:59                                   ` YASUAKI ISHIMATSU
2017-10-16 20:27                                     ` Thomas Gleixner
2017-10-30  9:08                                       ` Shivasharan Srikanteshwara
2017-11-01  0:47                                         ` Thomas Gleixner
2017-11-01 11:01                                           ` Hannes Reinecke
2017-10-04 21:10                             ` Thomas Gleixner
  -- strict thread matches above, loose matches on Subject: below --
2017-08-08 19:24 YASUAKI ISHIMATSU

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=78ce7246-c567-3f5f-b168-9bcfc659d4bd@gmail.com \
    --to=yasu.isimatu@gmail.com \
    --cc=axboe@kernel.dk \
    --cc=hare@suse.de \
    --cc=hch@lst.de \
    --cc=kashyap.desai@broadcom.com \
    --cc=keith.busch@intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=marc.zyngier@arm.com \
    --cc=mpe@ellerman.id.au \
    --cc=peterz@infradead.org \
    --cc=shivasharan.srikanteshwara@broadcom.com \
    --cc=sumit.saxena@broadcom.com \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).